Kociemba Robert H T-Bird II — Keymar, MD

What happened

Several witnesses observed the experimental, amateur-built airplane in a spin before they lost sight of it when it descended behind a row of trees. Another witness, who heard the engine but did not see the airplane in flight, stated that it sounded like it was "overloaded and struggling." Examination of the airframe revealed severe corrosion on the airframe structural tubing; however, there was no evidence of preimpact mechanical failure. Examination of the two-cylinder engine revealed that the aft cylinder, and the carburetor bowl that supplied fuel to that cylinder, were devoid of fuel, indicative of fuel starvation. Water and particulate contamination was found throughout the fuel system. Fuel sample analysis revealed that the fuel was 92 octane and contained about 9 percent ethanol. The contamination levels were sufficient to result in fuel starvation to one cylinder, and resulted in a complete loss of engine power. The complete loss of power in the rear-mounted engine at low altitude resulted in a pitch-up of the airplane, a reduction of airspeed, and an aerodynamic stall and spin from which the pilot could not recover. About 4 months prior to the accident the engine manufacturer issued guidance allowing for up to 10 percent ethanol blended fuels to be used; however, the owners were urged to confirm with the airframe manufacturer that ethanol blended fuels are allowed. No written guidance by the airframe manufacturer was located concerning the use of ethanol and no entry was located in the airplane maintenance record indicating that any change had been made to the airplane. Postmortem toxicology testing on the pilot was consistent with the use of a short-acting sleep aid the night prior to the accident and recent use of an over-the-counter antihistamine with impairing effects, likely for treatment of seasonal allergy symptoms. The sleep aid was unlikely to have resulted in impairment on the day of the accident, but the antihistamine could have adversely affected the pilot’s actions in response to the loss of power. The pilot did not possess a current airman medical certificate.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.